(1) Field of the Invention
This invention relates to an improved ribbon cartridge for use in a printing machine, and, more particularly, to a self-contained ribbon cartridge for use in a printing calculator of the type having a ribbon quantity sensing and reversing lever wherein the improved ribbon cartridge may be inserted into the printing machine with the ribbon taut, the spools immobilized, and the spools locked and oriented in a preselected and preferred position.
(2) Description of the Prior Art
The usual construction of a calculator printing mechanism prevents the insertion of ribbon in a self-contained cartridge. The mechanism construction is comprised of drive gears with axles attached thereto. Usually, a spool with an inked ribbon stored thereon is placed on the axle of one drive gear and a take-up spool is placed on the axle of the other drive gear. Typically, the spools have to be reoriented by rotation on the axles to properly seat them on engaging means located on each drive gear. In so inserting and reorienting the ribbon the inserter's hands often become soiled with ink from the ribbon. Also, the ribbon is sometimes loose and not properly taut after installation necessitating that the ribbon installer extend a hand into the printing mechanism at the location of either the take-up spool or the supply spool and adjust the tension on the ribbon.
Recently, self-contained ribbon cartridges have been developed for use in printing machines such as the printing electronic calculator. Such cartridges may perhaps possess various means for immobilizing the spools on which the inked ribbon is stored. However, no means is provided for positioning each spool on which ribbon is stored in a preselected and preferred position or orientation with respect to the cartridge such that when the cartridge is inserted into the printing machine of a calculator which has had its drive gears and engaging means thereon preoriented, adjustment or reorientation of the relative positions of the spools is unnecessary. This drawback wherein reorientation of the spools into a preselected position for insertion into the printing machine is necessary causes inconvenience to the operator of the calculator. In most instances, the relative positions of the two spools must be adjusted so that the cartridge can be seated within the printing machine and engage the drive gears for proper operation and movement of the individual spools within the cartridge.
The usual construction of a calculator printing machine prevents the random insertion of ribbon in a self-contained cartridge because the ribbon spools have engaging means thereon such as protruding fingers which must mate with other engaging means on the drive gears such as receptacles before the cartridge is properly seated for correct operation. Hence, heretofore means for reorienting the positions of these spools such as accessible ridged knobs connected to the spools were needed to properly seat the ribbon cartridge within the printing machine.
A ribbon cartridge in accordance with the present invention eliminates the necessity of having to reorient the ribbon spools prior to or after insertion of the cartridge into the printing machine.